Update DavidAnson/markdownlint-cli2-action action to v20 (#1078)

| datasource  | package                             | from    | to      |
| ----------- | ----------------------------------- | ------- | ------- |
| github-tags | DavidAnson/markdownlint-cli2-action | v19.1.0 | v20.0.0 |

Signed-off-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>
Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

.github/workflows/lint.yml

@@ -54,7 +54,7 @@ jobs:
         uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4.2.2
 
       - name: Lint Markdown
-        uses: DavidAnson/markdownlint-cli2-action@05f32210e84442804257b2a6f20b273450ec8265 # v19.1.0
+        uses: DavidAnson/markdownlint-cli2-action@992badcdf24e3b8eb7e87ff9287fe931bcb00c6e # v20.0.0
         with:
           config: .markdownlint-cli2.yaml
           globs: "**/*.md"